Thermal dependence of coercivity in granular CoNiCu glass coated microwires

Abstract Cu 80 Co 19 Ni 1 glass covered microwire samples with different geometric ratio, 0.13⩽ ρ ⩽0.5, has been investigated by using X-ray diffraction (XRD) and VSM technique. Our results show (i) the presence of FCC Co crystallites dispersed on the Cu matrix, (ii) the observation in all the samples of the coercivity, at room temperature, of the order of kA, exhibiting a maximum and decreased down to a value of the order of the room temperature one at 25 K. These results are discussed in terms of a distribution of superparamagnetic Co nanoparticles.